Grade assist or grade logic algorithms function as part of vehicle braking systems to prevent a vehicle from unintentionally accelerating on a downhill grade. Grade logic algorithms can automatically supplement engine braking, for example, by downshifting the vehicle transmission, in order to maintain constant vehicle speed when the vehicle travels on the downhill slope without excessive use of vehicle brakes. In the absence of grade logic, the vehicle could accelerate down the grade due to gravitational forces despite the desire of the driver to maintain vehicle speed.
Existing grade logic algorithms are designed to suspend the transmission-based assistance to engine braking and upshift the transmission if, for example, the engine exceeds a threshold revolution per minute (RPM) level. Though cancellation of grade logic in these situations can prevent engine noise and sluggish vehicle response to driver commands, the vehicle will once again be subject to accelerating on the downhill grade despite the driver's intention to maintain vehicle speed.